The Collaborative International Dictionary of English v.0.48:

Riddle \Rid"dle\, v. t.
   To explain; to solve; to unriddle.
   [1913 Webster]

         Riddle me this, and guess him if you can. --Dryden.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Riddle \Rid"dle\, v. i.
   To speak ambiguously or enigmatically. "Lysander riddles very
   prettily." --Shak.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Riddle \Rid"dle\ (r[i^]d"d'l), n. [OE. ridil, AS. hridder; akin
   to G. reiter, L. cribrum, and to Gr. kri`nein to distinguish,
   separate, and G. rein clean. See Crisis, Certain.]
   1. A sieve with coarse meshes, usually of wire, for
      separating coarser materials from finer, as chaff from
      grain, cinders from ashes, or gravel from sand.
      [1913 Webster]

   2. A board having a row of pins, set zigzag, between which
      wire is drawn to straighten it.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Riddle \Rid"dle\, v. t. [imp. & p. p. Riddled (r[i^]d"d'ld);
   p. pr. & vb. n. Riddling (r[i^]d"dl[i^]ng).]
   1. To separate, as grain from the chaff, with a riddle; to
      pass through a riddle; as, riddle wheat; to riddle coal or
      gravel.
      [1913 Webster]

   2. To perforate so as to make like a riddle; to make many
      holes in; as, a house riddled with shot.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Riddle \Rid"dle\, n. [For riddels, s being misunderstood as the
   plural ending; OE. ridels, redels. AS. r[=ae]dels; akin to D.
   raadsel, G. r[aum]thsel; fr. AS. r[=ae]dan to counsel or
   advise, also, to guess. [root]116. Cf. Read.]
   Something proposed to be solved by guessing or conjecture; a
   puzzling question; an ambiguous proposition; an enigma;
   hence, anything ambiguous or puzzling.
   [1913 Webster]

         To wring from me, and tell to them, my secret,
         That solved the riddle which I had proposed. --Milton.
   [1913 Webster]

         'T was a strange riddle of a lady.       --Hudibras.
   [1913 Webster]

WordNet (r) 3.0 (2006):

riddle
    n 1: a difficult problem [syn: riddle, conundrum, enigma,
         brain-teaser]
    2: a coarse sieve (as for gravel)
    v 1: pierce with many holes; "The bullets riddled his body"
    2: set a difficult problem or riddle; "riddle me a riddle"
    3: separate with a riddle, as grain from chaff [syn: riddle,
       screen]
    4: spread or diffuse through; "An atmosphere of distrust has
       permeated this administration"; "music penetrated the entire
       building"; "His campaign was riddled with accusations and
       personal attacks" [syn: permeate, pervade, penetrate,
       interpenetrate, diffuse, imbue, riddle]
    5: speak in riddles
    6: explain a riddle